O, o-diloweralkylphosphorodithiomethyl-(poly) chlorophenoxyacetates



United States Patent 3,372,210 0,0-DILOWERALKYLPHOS?HORODITHIOMETH-YL-(POLY) CHLOROPHENOXYACETATES Arnold D. Gutman, Oakland, and Thomas L.Snell, Hayward, Calif., assignors to Staufier Chemical Company,

New York, N.Y., a corporation of Delaware No Drawing. Filed Sept. 23,1964, Ser. No. 398,762 5 Claims. (Cl. 260-951) ABSTRACT OF THEDISCLOSURE Compounds having the general formula:

wherein R and R are lower alkyl, X is selected from the group consistingof hydrogen and halogen, preferably chlorine, and n is an integer from 1to 5, inclusive. The compounds are particularly effective as herbicidesin the control of grasses and broadleaf plants with both preemergenceand post-emergence activity. Typical compounds are 0,0 dimethylphosphorodithioylmethyl-pchlorophenoxyacetate, 0,0dimethylphosphorodithioylmethyl-2,4,S-trichlorophenoxyacetate and 0,0diisopropylphosphorodithioylmethyl-p-chlorophenoxyacetate.

This invention relates to certain new and novel organic compounds whichmay be used as herbicides. More specifically, this invention relates tocertain substituted phenoxydithioylphosphate esters and to the utilityof such compounds in herbicidal compositions.

The invention relates to compounds of the general formula:

ROS

3,372,210 Patented Mar. 5, 1968 ice 0,0-dimethylphosphorodithioate, 10.3g. (0.05 mole) parachlorophenoxyacetyl chloride and 150 ml. of benzenewere combined. The mixture was cooled to 0 C. in an ice-bath and 3.9 g.(0.05 mole) of pyridine was added drop-wise into the stirred solution atsuch a rate that the temperature was maintained below 10 C. After theaddi tion was completed, the mixture was washed with two 100 ml.portions of water, dried over anhydrous magnesium sulfate, and thebenzene evaporated on a steam bath. There was obtained 15.1 g. (84.5% oftheory) of 0,0dimethylphosphorodithioylmethyl p chlorophenoxyacetate, asemi-solid.

The following is a table of the compounds prepared according to theaforedescribed procedure. Compound numbers have been assigned to eachcompound and are used throughout the balance of the application.

TABLE I R O S O 1 /PSCH2O COHQO R O Xn Compound R R 1 X1.

CH3 CH3 4-01 0H: CH3 2,4-di-C CH3 CH3 2,4,5-tri-Cl 1-C H1 i-CaH7 4-ClNo. 1 prepared in the example.

As previously mentioned, the herein described novel compositionsproduced in the above described manner are phytotoxic compounds whichare useful and valuable in controlling various plant species. Thecompounds of this invention were tested as herbicides in the followingmanner.

Pre-emergence herbicide test.The seeds of crab grass, annular bluegrass,watergrass, red oats, pigweed, Indian mustard and curled dock wereplanted in individual rows one-half inch deep in Santa Cruz sandy loamsoil contained in compressed paper flats. Enough seeds were planted togive about thirty to fifty plants each of the weed species in each flat.The flats were watered after planting. The following day each flat wassprayed at the rate of 20 pounds of the candidate compound under test in80 gallons of solution per acre. An atomizer was used to spray thesolution on the soil surface. Two weeks later the degree of weed controlwas determined by comparing the amount of germination and growth of eachweed in the treated flats with weeds in several untreated control flats.The results of this test are reported in Table II.

TABLE II.PREEMERGENCE ACTIVITY RATE 20 LBS./ A.

Compound Crab grass Annual Water grass Red oats Pigweed Indian CurledNumber bluegrass mustard dock iii i iii iii iii iii iii +:severe injuryor death.

+ +=m0derate in ury, +:slight injury.

The compounds of the present invention may be used in accordance withthe following non-limiting example.

EXAMPLE 1 Preparation of0,0-dimethylphosphorodithioy[methylp-chlorophenoxyacetate.-A 500 ml.round-bottom flask was equipped with a stirrer, thermometer, anddropping funnel. In the flask, 9.4 g. (0.05 mole) hydroxymethylgrass,foxtail and curled dock at 2 pounds per acre.

Post-emergence herbicide test.The seeds of crab grass, watergrass, redoats, Indian mustard, curled dock and 3 pinto bean were planted inindividual rows in Santa Cruz sandy loam soil as described in thepre-emergence test, supra. After growing for tWo weeks under greenhouseconditions the plants were four to six inches tall. Thereafter, thecandidate test compound was applied to 4 described herein as will beapparent to those skilled in the art to which it pertains. It isaccordingly intended that the present invention shall only be limited bythe scope of the appended claims.

We claim:

5 the foliage by means of an overhead spray while the flat 1.Composition of matter corresponding to the formoved under the spray on amoving table. A concentraula; tion of 0.5% of active compound in thespray was used at a rate equivalent to approximately 60 lbs./ acre. TwoR0 s 0 weeks after treatment the injury results were recorded I Q uslnga similar ratrng system as used in the pre-emergence test. Table 111lists the results obtained therefrom.

R 0 Xn TABLE IIL-POST-EMERGENCE ACTIVITY RATE 60 LBSJA.

Compound Crab grass Water grass Red oats Indian Curled dock Pinto beanNumber mustard fir iii 1 iii iii +++=severe injury or death. ++=moderateinjury. +=slight injury.

The compounds of the present invention were found to give excellentcontrol, 85 to 100 percent, at the apwherein R and R are lower alkyl, Xis chlorine and n is an integer from 1 to 5 inclusive.

plication rate of 2 pounds per acre for lam'os quarter, The compound,O,0-dimethylphosphofodiihioyl pigweed, mustard and curled dock.methyl-p-chlorophenoxyacetate The compounds of the present inventionfind particular 4 i fi ig g ggg fi me -,-1cop e.

u 1 1 y as pre emergence or post-emergence herbicides and 4. Thecompound O,odimethylphosphorodithioy1 may be applied in a variety ofways at various concentrations. They may be combined with suitablecarriers and applied as dusts, sprays or dreuches. The amount appliedwill depend upon the nature of the weeds or plants to be controlled andthe rate of application may vary from 1 to 80 pounds per acre. Oneparticularly advantageous way of applying the compounds is as a narrowband along a row crop, straddling the row.

Various changes and modifications may be made without departing from thespirit and scope of the invention methyl-2,4,5-trichlorophenoxyacetate.

5. The compound,0,0-diisopropylphosphorodithioylmethyl-p-chlorophenoxyacetate.

References Cited UNITED STATES PATENTS 3,168,436 2/1965 Chupp 260-952 XCHARLES B. PARKER, Primary Examiner. B. BILLIAN, A. H. SUTTO, AssistantExaminers.

